This situation I've found to exist on California State Route 247 in Lucerne Valley related to Barstow Road and Old Woman Springs Road. Excerpt taken from the blog I wrote regarding California State Route 247:
"The first segment of California State Route 247 begins at California State Route 62 in Yucca Valley and terminates at California State Route 18 in Lucerne Valley via Old Woman Springs Road. The second segment of California State Route 247 begins at California State Route 18 in Lucerne Valley and follows Barstow Road to Interstate 15 in Barstow. The definition of the two segments of California State Route 247 creates an odd situation where California State Route 247 crosses over itself in Lucerne Valley at the intersection of Old Woman Springs Road and Barstow Road."
"The two defined segments of California State Route 247 created a crossover in Lucerne Valley. California State Route 247 continues west of Barstow Road along Old Woman Springs Road to California State Route 18 via approximately Postmiles SBD 44.615-44.85. The Postmiles along California State Route 18 begin to ascend again from California State Route 18 at Postmile SBR 44.86 northward on Barstow Road towards Barstow. Normally a situation like this would be handled with "S" prefix Postmiles to denote a Spur State Highway."
I snipped images of the crossover in Lucerne Valley on images 10-12 in the below blog:
https://www.gribblenation.org/2019/04/california-state-route-247.html?m=1
Utah SR 190 does a weird loop in Brighton, Utah that involves a backtrack. The route is nominally the road up Big Cottonwood Canyon to Guardsman Pass, but the spur through Brighton is mileposted as part of the main route.
Washington SR 100 is signed with a "Loop" directional and ends at itself, so I guess that counts.
As for physically crossing over, SR 504 has a loop near the Johnston Ridge Observatory on Mount St. Helens.
US 441 does this leaving Gatlinburg TN in the Smoky Mountains.
Not exactly the same but I-8 and I believe I-85 (someone can correct me on that one) have places where the opposite carriageways cross over themselves and return back. I-8 in California and I-85 in NC I think.
iPhone
Would 10 in Los Angeles fit this, due to former US 60/70/99 between US 101 and I-5 being added to the 10 route definition in 1968 (after the removal of the on-paper spur I-110)?
Essentially it is some wierd thing where:
FHWA: I-10 follows San Bernardino Freeway to I-5, then Golden State Freeway with I-5, then Santa Monica Freeway to Route 1
California legislative route definition: Segment 1 is from Route 1 to I-5, but Segment 2 is from US 101 at the San Bernardino Split eastward.
- I-70 New Stanton and Breezewood
- I-76 Youngstown bump
US 16A, Iron Mountain Road :spin:
What about the Helix by the Lincoln Tunnel?
Whatever that route is (isn't it NJ-3 or something?), crosses over itself to get into the tunnel.
Quote from: bassoon1986 on May 18, 2023, 01:20:54 PM
US 441 does this leaving Gatlinburg TN in the Smoky Mountains.
Not exactly the same but I-8 and I believe I-85 (someone can correct me on that one) have places where the opposite carriageways cross over themselves and return back. I-8 in California and I-85 in NC I think.
You're correct about I-85. The carriageways cross over each other and each side has a (separate) rest area in the median (with right-side exits and entrances to reach it) connected to the state Vietnam veterans' memorial.
I'm assuming the OP isn't interested in things like highways that partially cross over themselves where a route changes direction through an interchange, similar to a TOTSO scenario, and one carriageway's connection is direct while the other one loops around. I'm thinking of something like here where the Fairfax County Parkway (VA-286) comes up from the bottom of the map and the northbound side crosses over the southbound side, goes around the loop ramp, and heads off to the left side of the map. (https://www.google.com/maps/@38.7593053,-77.2196531,16.32z/data=!5m1!1e2) The southbound carriageway feels less like a TOTSO due to the way the interchange is configured (although it does have an advisory speed sign that uses the word "Exit" rather than "ramp").
US 278 does so in Georgia east of Atlanta due to a rail line.
A-20 once crossed over itself between the Turcot interchange and the Mercier bridge, but since the former was reconstructed, it's no longer that way.
Also, routes going back to themselves are a Québec thing: QC 132, 169 and 368 all loop back to themselves (and in 368's case, it never ends).
US 131 nb and sb lines cross over and under themselves at I-196. Kind of like a DDI, but a freeway doing the crossovers.
US 101 in Astoria, Oregon does.
Quote from: zachary_amaryllis on May 19, 2023, 06:37:28 AM
What about the Helix by the Lincoln Tunnel?
Whatever that route is (isn't it NJ-3 or something?), crosses over itself to get into the tunnel.
NJ 495
I-95 used to at the northern I-695 junction. I-95 north does at both MA 128 junctions in Canton and Peabody
The new routing of US-33 in Ravenswood, West Virginia crosses over itself.
Quote from: bassoon1986 on May 18, 2023, 01:20:54 PM
US 441 does this leaving Gatlinburg TN in the Smoky Mountains.
Not exactly the same but I-8 and I believe I-85 (someone can correct me on that one) have places where the opposite carriageways cross over themselves and return back. I-8 in California and I-85 in NC I think.
iPhone
US-441 does, indeed, loop over itself on the way up a mountain headed south from Gatlinburg toward North Carolina.
I had always intended to take that trip when I lived in GA, but I never got around to it.
Technically, US-1 does this at its interchange with I-93 in downtown Boston. You could argue that any trumpet or cloverleaf interchange in which a route changes pavement falls into the same category and therefore it doesn't count. But this one is different because US-1 crosses over itself in both directions (northbound and southbound), not just one, as would be typical for a trumpet interchange that marks the beginning/end of a concurrency.
I-74 and I-80, at the same interchange.